[CVE-2026-74380][LOW] gpu: host1x: Fix iommu_map_sgtable() return value check [ Upstream

[CVE-2026-74380][LOW] gpu: host1x: Fix iommu_map_sgtable() return value check [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74380
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: gpu: host1x: Fix iommu_map_sgtable() return value check [ Upstream
Commit: 5f3985c2a500df3126cb12a2e0ccf26a40bc495d
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5f3985c2a500df3126cb12a2e0ccf26a40bc495d
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74380
Analysis date: Sun, 16 Aug 2026 02:04:01 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: YES

Summary:
Incorrect handling of `iommu_map_sgtable()` errors in host1x `pin_job()` can allow GPU job setup to continue after an IOMMU mapping failure, leading to local device or driver denial of service without evidence of privilege escalation.

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ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-74380 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74380

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: LOW
Manual review required: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-74380	LOW	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-252;CWE-703;CWE-681;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'host1x pin_job could incorrectly treat a failed iommu_map_sgtable() call as success because negative error returns were not checked after the IOMMU API changed. This may let GPU job setup continue with an unmapped IOVA and can lead to IOMMU faults or device job failure. For the CVSS the PR:L is used because a local process normally needs access to the host1x GPU job submission interface to reach this path. The issue is not network reachable and does not show a concrete UAF, OOB write, information leak, or arbitrary write primitive. Impact is mainly denial of service for the GPU or driver path, with no supported evidence for privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)  SKIP CVE-2026-74380 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: ad8f36e4b6b1c826a0daa5fda2c5839205b5aa8b YES  NO NO unknown 	MAYBE	SIMPLEFIX DMAorINTERRUPT HARDWARE LINUS 	-	-	checked

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ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1. A local process with access to the host1x GPU job submission interface may reach `pin_job()`.
* Availability impact realistic: +1. Continuing after a failed IOMMU mapping can plausibly cause IOMMU faults, GPU job failure, or driver/device disruption.
* Hard or unreliable trigger: -1. The bug requires `iommu_map_sgtable()` to fail or return a value affected by the type mismatch, which is an error-path condition rather than a normal fast path.

Paranoid additional signal:

* DMA/device-management state inconsistency: +1. The affected code is an IOMMU mapping path for GPU jobs, so mishandling the returned mapping result can leave device-visible state inconsistent.

Signals not awarded:

* Remote reachable: +0. No network path.
* Firmware-mediated external influence: +0. No firmware-controlled input is required by the patch.
* Generic memory corruption: +0. No UAF, double free, OOB write, arbitrary write, or type confusion is shown.
* Privilege escalation plausible: +0. No concrete LPE primitive is supported.
* Confidentiality impact: +0.
* Integrity impact: +0.

Call-site confidence: medium. The changed function and immediate IOMMU mapping use are visible, but the full userspace submission path and device-node permissions are not included.

## 3. Reachability analysis

The likely trigger is local access to a host1x GPU job submission path on affected NVIDIA Tegra style systems. Containers or namespaces only matter if the relevant GPU device node is passed through to the container. The issue is not remotely reachable and is not in a common networking or filesystem path. Realistic exploitation requires a failed IOMMU SG-table mapping or an oversized return conversion condition, so the trigger is less reliable than a normal user-controlled ioctl crash.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like driver error-handling issue, not an Important-class kernel vulnerability. The realistic impact is GPU job failure, IOMMU fault, or local device/driver DoS. Theoretical concern comes from continuing with an invalid or unmapped IOVA in a DMA-adjacent path, but the patch does not show attacker-controlled memory corruption, stale object reuse, page ownership violation, or privilege escalation.

## 5. One-sentence report phrase

Incorrect handling of `iommu_map_sgtable()` errors in host1x `pin_job()` can allow GPU job setup to continue after an IOMMU mapping failure, leading to local device or driver denial of service without evidence of privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED. NO MANUAL CHECK REQUIRED COULD BE AUTOCLOSED. The issue is local, hardware-specific, error-path dependent, and lacks a concrete memory corruption or security-boundary bypass primitive.

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UPSTREAM PATCH SUMMARY
======================================================================

Patch: gpu: host1x: Fix iommu_map_sgtable() return value check [ Upstream
Commit: 5f3985c2a500df3126cb12a2e0ccf26a40bc495d
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5f3985c2a500df3126cb12a2e0ccf26a40bc495d

Changed files:
  drivers/gpu/host1x/job.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5f3985c2a500df3126cb12a2e0ccf26a40bc495d

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-74380 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74380

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 1
  Paranoid ActionableScore: 2

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).